Discuss the role of CPAP in diseases of the elderly

CPAP delivers a single continuous positive pressure throughout the respiratory cycle through a nasal or oro-nasal interface. It acts as a pneumatic splint for the upper airway, recruits collapsed alveoli and increases functional residual capacity, reduces the work of breathing and, by raising intrathoracic pressure, reduces left ventricular preload and afterload.

CPAP is not a ventilator. It provides no inspiratory pressure support and therefore does not augment tidal volume or clear carbon dioxide — hypercapnic respiratory failure requires bilevel NIV (BiPAP), not CPAP. This distinction is a favourite viva question. Obstructive Sleep Apnoea — the Principal Indication

OSA is defined by an apnoea–hypopnoea index (AHI) > 5/hour with excessive daytime sleepiness or neurocognitive/behavioural disturbance not attributable to another cause.

OSA is far commoner in old age: approximately 50% of older people have an AHI > 5 and 20% have an AHI > 15, compared with about 10% of younger adults. The rise is explained by increased upper-airway collapsibility with age — loss of pharyngeal dilator muscle tone and altered reflexes, edentulism, increased pharyngeal fat deposition and post-menopausal hormonal change (after which the sex difference disappears).

The classical triad is unreliable in the elderly: the proportion of OSA patients who do not snore rises after 50; daytime sleepiness is confounded by comorbidity and drugs; and the Epworth Sleepiness Scale includes driving items that are unsuitable for many older people. Suspect OSA instead from nocturia, morning headache, non-restorative sleep, unexplained falls, refractory hypertension and worsening cognition.

Polysomnography is the gold standard; simplified home respiratory polygraphy is cheaper but less satisfactory a priori in the elderly because of the high background frequency of restless legs and other sleep disorders and the practical difficulty of accommodating equipment at home — each case must be judged individually.

CPAP is the treatment of choice for OSA. It abolishes snoring and apnoeas, improves gas exchange and normalises sleep architecture, and in older adults improves alertness, cognitive processing, memory and executive function.

Adherence is the principal limitation — 40–50% of patients do not use the device adequately. Importantly, compliance in older patients is no worse than in the young, including in series of patients with dementia or cognitive impairment; practical difficulties such as applying the mask are solved by patient and caregiver training.

Adjunctive measures: weight reduction in the obese, positional therapy, avoidance of alcohol and sedatives (especially benzodiazepines and Z-drugs), treatment of nasal obstruction, and mandibular advancement devices where dentition allows.

OSA is epidemiologically linked in older people to hypertension, ischaemic stroke, heart failure, atrial fibrillation and ischaemic heart disease — and in advanced age these cardiovascular manifestations may be the only presentation of OSA. A prospective study showed that long-term CPAP reduced cardiovascular mortality in elderly OSA patients.

Heart failure: Pathy's lists sleep-disordered breathing as a comorbidity of heart failure that increases mortality risk, with CPAP as the key management. CPAP reduces preload and afterload, improves left ventricular ejection fraction and reduces sympathetic activation.

Acute cardiogenic pulmonary oedema is the other major acute indication: CPAP at 5–10 cmH O improves 2 oxygenation, reduces the work of breathing and reduces the need for intubation, and is often preferable to intubation in the frail elderly patient.

Cognition and dementia: sleep-disordered breathing is associated with Alzheimer-type dementia and with agitation in institutionalised patients with dementia. CPAP is associated with improved neurocognitive performance and, on imaging, with favourable changes in cortical thickness and default-mode-network connectivity.

Depression, epilepsy and falls: untreated OSA in the elderly is correlated with worsening depressive symptoms, poor seizure control and frequent falls — all potentially modifiable by effective CPAP therapy. Other Uses, Contraindications and Practical Issues

Other clinical roles: obesity hypoventilation syndrome (though bilevel NIV is preferred if hypercapnia is established), type 1 hypoxaemic respiratory failure including pneumonia and COVID-19, post-operative atelectasis and prevention of post-extubation failure, and chest-wall trauma. In multiple sclerosis and other neurological disease, CPAP and BiPAP address the OSA that commonly underlies fatigue.

Contraindications: reduced consciousness and inability to protect the airway, facial trauma or surgery, undrained pneumothorax, vomiting or high aspiration risk, haemodynamic instability, severe epistaxis, and recent upper gastrointestinal surgery. Established hypercapnic acidosis is a contraindication to CPAP in favour of BiPAP.

Complications: mask pressure sores over the nasal bridge (a particular hazard on thin, fragile, ageing skin), nasal dryness, epistaxis, conjunctivitis from leak, gastric distension and aspiration, claustrophobia and precipitation or worsening of delirium.

Geriatric-specific practical points: humidification is essential; the interface must be fitted around dentures and facial contours; arthritis and poor dexterity affect strap handling; cognitive impairment demands caregiver involvement; and CPAP therapy should be introduced with a structured education and early-follow-up programme, since adherence in the first week predicts long-term use.

Ethical framing: in the frail or severely demented patient, CPAP may be entirely appropriate as a ceiling of care — the maximum agreed level of respiratory support short of intubation — and this should be documented in advance.

Unresolved question, as stated in the textbook: what remains to be established is whether CPAP in seniors corrects the symptoms caused by OSA and modifies cardiovascular comorbidity to the same degree as in younger patients.